Systems Engineering at the Nanoscale
Jennifer L. Sample and Harry K. Charles Jr.
anotechnology has become ubiquitous in advanced technology
and advanced product development. Nanotechnology exploits
the properties of materials with at least one dimension at the
nanoscale, typically in a novel and controllable way. As a result, nanotechnology has
the ability to affect materials and structures as part of complex systems that can
influence actions in the macroscopic world. This article explores nanotechnology and
its emergence into systems engineering, highlighting attributes of the technology that
may play a significant role in APL-developed systems of the future.
INTRODUCTION
A system is a composite of different elements that
when brought together yield results that are not obtainable from the elements alone.1 The function of systems
engineering is to guide the development of individual
components into robust and efficient systems capable
of autonomous operation as complex systems, where
complex systems are defined as systems in which elements are diverse and have intricate relationships with
each another. Nanotechnology refers to the creation of
functional materials, devices, and systems via control
of matter on the nanometer-length scale (nominally
1–100 nm) and exploitation of novel phenomena and
properties (physical, chemical, biological) at that length
scale. In general, nanotechnology begins with nanoscience: the study of material properties and their interactions at the nanoscale and how they can be exploited.
50
Once the properties of nanostructures are well characterized and can be reproducibly fabricated, those properties can be exploited as a technology.
Two important concepts define a system:
1. The system has properties or attributes that cannot
be associated with any of its components.2
2. The description of the system function is less complex than the functional descriptions of the system
components. These concepts or properties are called
emergent properties of the system.3
Emergence in the engineering disciplines is an
expected outcome. Emergence can also occur in nanomaterial systems.
For example, a microprocessor chip system can perform millions of arithmetical functions per second
JOHNS HOPKINS APL TECHNICAL DIGEST, VOLUME 31, NUMBER 1 (© 2012)
under precise control of a software program. These
mathematical functions are a straightforward manifestation of the input and output behavior of the software
code. This description is much simpler than a description of the microprocessor chip states through which
the chip would pass as the function is computed under
the direction of the software code. Such component
descriptions—regardless of the level considered, from
individual quantum levels to gate or machine language
functions—are much more complex than the description of the mathematical function itself. Microprocessors, however, are typically part of multiscale systems
such as cellular phones and automotive sensors and
similarly could be part of systems linking nanotechnology to society.
This article will describe the development of nanotechnology for small systems or components at APL.
Examples include physiologically responsive polymers,
which release drugs only in response to a need-based
physiological stimulus;4 nanoporous DNA sensors,
which electrically detect DNA segments binding to a
known segment;5 and biologically generated nanoscale
cellulose composites, which provide strong transparent
materials for structural or biomedical applications.6 All
of these technologies are currently under development
at APL.
COMPLEX SYSTEMS
Complex systems or complex adaptive systems have
been studied extensively for almost 40 years.7 They
trace their origins to the beginnings of chaos theory in
1890 by Jules Henri Poincaré8 (1854–1912), a professor
of mathematics at the University of Paris from 1881 to
1912, and to the work in the 1960s of Edward Norton
Lorenz9 (1917–2008), mathematician, meteorologist,
and professor at Massachusetts Institute of Technology. To define a complex system we must consider the
concept of upward predictability. Upward predictability
implies that an analysis of interactions at the component level will yield a simple explanation of the phenomena observed at the system level. Systems that can
be analyzed in this manner are upwardly predictable.
Complex systems often are not upwardly predictable.
The effects of interactions at the component level are
correlated in complex ways to the phenomena occurring
at the system level. This lack of upward predictability,
coupled with emergence concepts, is the hallmark of a
complex system.
Complex systems can be engineered by humans
or they can occur naturally. Representative humanengineered systems include many APL systems, including missile defense and spacecraft systems such as the
Standard and Tomahawk missiles, the Midcourse Space
Experiment (MSX, a DoD satellite), and the MErcury
Surface, Space ENvironment, GEochemistry and Rang-
JOHNS HOPKINS APL TECHNICAL DIGEST, VOLUME 31, NUMBER 1 (© 2012)
ing (MESSENGER) probe, a mission to the planet Mercury. Naturally occurring complex systems can range
from biological entities to meteorological events. Virtually all important properties of engineered systems are
emergent. The primary difference between engineered
and naturally occurring systems is that in human-produced systems, the emergent properties are produced
intentionally. Yet other real differences exist: humanengineered systems are often functionally fragile and do
not hold up well in the environment in which they are
used, whereas natural systems seem to be more robust,
flexible, and adaptable. These differences are due in
part to the top-down or hierarchical design approach3
used in human-engineered systems. At each level, performance goals are set and then subcomponents are
added with the needed properties to achieve the performance at the next upward level. For each of the subcomponents, the same is done with sub-subcomponents
and so on.
In contrast, nature designs systems from the bottom
up. Existing or modified components are put together
with no known performance constraints or functionality
goals in mind. The resultant system (assemblage) either
survives in the environment or dies (trial and error and
survival of the fittest). Nature’s designs are not always
perfect, but surviving systems perform the required
functions, and nature does not have to work against
budget and schedule constraints. The description in this
article of the latest developments in microelectronics
and nanotechnology explores the application of natureemulating systems built by the self-assembly of fundamental components versus the top-down approach of
conventional human-engineered systems. Both system
types play important roles in all areas of science and
engineering development.
NANOTECHNOLOGY
The properties of nanoscale materials differ from
their macroscopic counterparts. One ubiquitous difference is higher surface area; nanostructures can have as
much as 90% of the atoms at the surface (Fig. 1).
This increased surface area leads to improved catalytic performance at the nanoscale for catalytic materials. It also leads to a maximization of relevant surface
effects, such as capillary forces and electrostatic attraction, which can be exploited to assemble nanoparticles
into functional, hierarchical arrays.10
Variance in optical properties with nanomaterial size
and shape has been known for centuries in the use of gold
and silver nanoparticles as pottery glazes and stainedglass pigments.11 Gold and silver exhibit size-dependent
optical properties because they support a surface plasmon—a collective oscillation of free electrons in the
material that can resonate, absorbing light in the visible
spectrum. In recent decades, these materials have found
51­­­­
J. L. SAMPLE AND H. K. CHARLES JR.
Macro
1 cm
1 mm
0.1 mm
Micro
Size scale
10 m
1 m
0.1 m
Nano
10 nm
1 nm
0.1 nm
0
20
40
60
80
Atoms at the surface (%)
100
Figure 1. Nanoscale particles have a much larger percentage
of atoms at the surface (76%) than macroscopic (millimetersized) particles, which have approximately 0% of atoms at
the surface.11
extensive utility in sensing applications.12, 13 This surface plasmon gives rise in part to the surface-enhanced
Raman scattering effect, which has been exploited by
APL researchers to detect chemical or biological signatures of interest to APL sponsors.14, 15
Quantum confinement, or confinement of electrons
in a material as a result of finite size (rather than bulk
“infinite” size), leads to many interesting nanoscale
effects. Semiconductors exhibit size-dependent optical properties as a result of quantum confinement. The
term “quantum dot” is used in the context of referring
to these materials, as they fluoresce at size-dependent
wavelengths. These materials have been applied commercially as fluorescent biomarkers used for biomedical
imaging, and they have been used at APL for sensing
and tagging applications.
There are many nanoscale devices that perform functions in response to stimuli or integrate the functionality
of multiple counterparts to perform a function or make
a measurement. These are small, complex nanosystems.
Three primary examples are nanowire sensors, biomimetic nanomaterial systems, and DNA “walkers” that
52
exploit the self-assembling material properties of DNA
to enable a small “robot” to perform functions such as
walking down a track.16
APL researchers have developed functional nanomaterials and devices to address critical challenges
in homeland protection. For example, one project,
the Nanoporous DNA Sensor, uses nanotechnology to achieve rapid, straightforward DNA matching.
Nanoscale pores are functionalized with complementary
DNA, and the size of the pores is small enough that DNA
binding inside the pore will change impedance through
the porous membrane in a detectable way. This technology is envisioned as an alternative to DNA microarray
technology, providing the advantage of reduced sample
preparation requirements, which will be useful in rapid
screening scenarios. Another APL project uses electrodeposited bismuth nanowires to detect radiation. Incident gamma rays generate detectable electrical current
in these materials. These bismuth nanowire arrays have
the significant advantage of being less expensive to produce than the current technology, which involves large
single-crystal semiconductor detectors. In addition to
these sensor nanowire applications, metal nanotubes are
being investigated at APL for high-energy-density thinfilm battery applications. These thin-film battery nanotubes are filled with battery chemicals, and they can be
geometrically engineered to minimize battery inefficiencies such as diffusion-limited transport between anode
and cathode.17
Researchers hoping to mimic the desirable functionalities of naturally occurring biological systems have
created various nanomaterial systems. For example, the
gecko lizard demonstrates the remarkable ability to defy
gravity by scaling walls and walking on ceilings despite
its relatively high mass (especially when compared with
insects). Furthermore, this organism can scale surfaces
of varying roughness in varying ambient environments
such as low or high humidity. Research into the biological gecko foot and the structures of insects’ feet has
revealed the presence of small hair-like structures whose
sizes scale inversely with the creatures’ mass foot-to-pad
area ratio, with the gecko’s foot hair structures consisting of flexible nanofiber-shaped hairs. Attempts to replicate these naturally occurring structures have integrated
many types of lithography and materials, from microelectromechanical system (MEMS) foot hairs to highaspect-ratio polymer nanofiber structures created from
a self-assembling polymer microsphere templated lithographic technique.18 At APL, researchers are mimicking nature to produce an “eye patch” for battlefield eye
injuries. Biologically generated nanoscale cellulose fiber
composites are being used to mimic the strong mechanical properties and simultaneously transparent optical
properties of the natural cornea.19
The types of materials described above can be considered individual components of larger systems, rather
JOHNS HOPKINS APL TECHNICAL DIGEST, VOLUME 31, NUMBER 1 (© 2012)
SYSTEMS ENGINEERING AT THE NANOSCALE
than nanosystems themselves. Roco20 has classified
nanotechnology into four generations: (i) nanomaterials fabrication, (ii) nanoscale phenomena exploitation,
(iii) nanotechnology-based devices, and (iv) complex
nanosystems. As a field, nanotechnology to date has certainly reached the third generation. The achievement
of the fourth generation will likely challenge the field
of systems engineering to accommodate these dynamic,
reconfigurable nanosystems with properties that do not
necessarily scale with size.
INTERFACING NANOTECHNOLOGY WITH THE
MACROSCOPIC WORLD
At the time of this writing, several systems involving
nanotechnology are under development for commercial
use, including lab-on-a-chip (LOC) technology and
hybrid nanoelectronics.
LOC technology has received considerable attention in the last two decades21 as a promising, highly
functioning diagnostic tool capable of providing fast
diagnostic information to medical professionals and
requiring minimally invasive sample collection. LOCs
incorporate many types of technology at many scales,
from sample collection (e.g., blood draw) to microfluidic
chip-level sample processing (e.g., separation of cellular
blood components from serum), to sensors for detecting biomarkers in the samples, to user interfaces. Thus
LOCs incorporating nanosensors or other nanotechnology are an example of nanotechnology interfacing with
the micro- and macroscales at the systems level.
Much has been reported about the potential of nanostructure-based electronics, including devices consisting
of supramolecular chemistry-based molecules connected
to nanostructures as a new molecular electronics-based
computing paradigm22 and devices that exploit the
semiconductor properties combined with the small
diameter and high aspect ratios of nanostructures such
as carbon nanotubes (CNTs).23 Commercial nanoelectronic devices are available (e.g., Nantero, Inc., http://
www.nantero.com/). However, manufacturability issues
remain a challenge for integrating some nanoelectronic
materials with current CMOS technology. Specifically,
it remains challenging to control the electronic structure of CNTs during the growth process, often requiring
the separation of semiconducting tubes from metallic
tubes or the time-intensive wiring of only the semiconducting tubes (after identification) in place. In addition,
many nanostructure growth procedures require high
temperatures (600–1000°C) or gases not typically compatible with conventional CMOS technology. Because
the CMOS device infrastructure is enormous, these
nanodevices have not made it into the mainstream and
thus are an example of a nanotechnology challenge with
respect to integration into a larger system.
JOHNS HOPKINS APL TECHNICAL DIGEST, VOLUME 31, NUMBER 1 (© 2012)
To incorporate nanoelectronic materials into mainstream device technology, the nanoelectronic materials
must be integrated into hybrid devices by using conventional integrated circuit processes. This process is very
challenging with CNTs, as a result of their varied electronic properties, but may not be as prohibitive with graphene. Graphene consists of a single sheet of graphite,
and it can be deposited at lower temperatures onto silicon or transferred mechanically.24 APL researchers are
working with graphene for several projects.
In addition to manufacturing challenges associated
with nanotechnology, the nanotechnology itself may
require additional considerations in the systems engineering process. Nanomaterials, because of their very
small size, are much more susceptible to thermal fluctuations and to weak, reversible forces than are their
macroscopic counterparts.
These susceptibilities can be exploited to create
materials and devices by using self-assembly. Selfassembly is a process that nanomaterials undergo
through which weak, reversible forces such as van der
Waals attractions, capillary forces, electrostatic interactions, and hydrophobic/hydrophilic interactions are
exploited to assemble larger structures from nanoscale
counterparts. Self-assembled monolayers (SAMs) are
an example of an early studied self-assembling system
in which molecules spontaneously form monolayers
onto substrates for which they have an affinity, e.g.,
sulfur-containing thiol molecules onto gold. With the
invention and maturity of atomic imaging techniques
such as scanning tunneling microscopy, these selfassembled monolayers were used initially to study the
positional bonding and thermal migration of molecules
on surfaces. Soon thereafter, however, it was discovered that these films could also be used to passivate
nanoparticles, thus preventing their aggregation, or
could be exploited to introduce new functionalities to
material surfaces.25
Beyond SAMs, self-assembly has been exploited
to create nanoparticle-based colorimetric DNA sensors, precisely shaped microstructures from the folding
of components engineered to self-assemble,26 complex structures made out of DNA (which readily selfassembles to strands with corresponding base pairs),
and metalized DNA grids with nanoscale dimensions.27
Because a strand of DNA will automatically form a helical structure with its corresponding base pair-matched
counterpart, computer scientists and materials scientists
have been able to exploit this material for its innate
self-assembling properties rather than for its biological function. In fact, it is possible to simply order the
desired strands so that one must only design the proper
sequence to create imaginable structures. DNA “smiley-face” structures have been formed in this way, by
engineering small crossing strands to force a long strand
to fold in programmed ways into the desired structure.
53­­­­
J. L. SAMPLE AND H. K. CHARLES JR.
54
Tim
e
Level/scale
When the DNA structure also
performs a complex function, this
structure becomes a system.
(Months–years)
Self-assembly has also been
Environment 4
exploited on a wide variety of
(system)
APL projects, most recently for
self-healing paint applications and
drug delivery. The self-healing
(Days–months)
Environment 3
paint has been created by APL
(subsystem)
researchers for naval applications.
The paint contains essentially
miniature metal “paint” cans,
(Hours–days)
Environment 2
which actually contain uncured
(devices/components)
polymer that cures upon contact
with air. The process of scratching the paint breaks open these
Environment 1
“cans” and releases the polymer,
(Minutes–hours)
(self-organization)
and the polymer flows to fill up
the scratch and then cures. The
Complexity
emulsification of the paint into
(nearly) identical microscopic Figure 2. Schematic representation of emergence and increasing complexity of nanotechdroplets is a wet chemical self- nology building blocks as they evolve into more complex structures or systems.
assembly process. Self-assembly is
being exploited to create physioframework for the implementation of working complex
logically responsive polymers, which release a drug only
systems at micro- and nanoscales. These same principles
in response to a physiological stimulus. Binding of the
also help the integration of micro- and nanosystems into
allergen or antibody of interest causes a conformational
the building blocks of larger-scale engineered systems.
change in the polymer, which releases the drug. Also
Figure 2 illustrates the emergence and the evolution of
at APL, chemiluminescent solid lipid nanoparticles
the complexity of systems as the size of the system’s comhave been created by using self-assembly, and these are
positional entities increases and the entities’ environbeing explored as a fluorescent or colorimetric assay for
ments change. Timescales of development also increase
inflammatory markers in the skin that may be indica28
with increasing system complexity and the expected
tive of disease, such as peroxides in skin cancer.
emergence behavior.
Self-assembly is of interest when nanotechnology is
Scale (or size) is a key element in all microelectronicbeing considered for use as a component of a greater
and
nanotechnology-based systems. Not only has shrinksystem. Because self-assembly is a naturally dynamic
ing
size
improved the performance of electronic devices
process that exploits forces that in many cases are of a
(integrated
circuits), but it has also reduced particle size
magnitude similar to the thermal energy of the system,
(diameter,
surface
area-to-volume ratio) in all matecare must be taken to understand and account for the
rial
systems
and
has
allowed significant breakthroughs
dynamic nature of the nanotechnology being used when
in
many
fields.
Today
these breakthroughs range from
engineering the system. Nanomaterials and related
materials
and
medical
breakthroughs to devices that
devices may be more dynamic than micro- or macroemulate
nature.
devices with similar functions. For this reason, strategies
Just as the invention of the planar process and the
such as redundancy or capability-based design (rather
integrated
circuit attributed to Kilby29, 30 and Noyce31, 32
than requirements-based design) might be necessary in
more
than
50 years ago were seminal moments in the
the systems engineering process.
microelectronic industry, the discovery of the CNT by
Iijima33, 34 in 1991 and the preceding development of the
atomic
force microscope by Binnig, Quate, and Gerber35
SYSTEMS ENGINEERING APPLICATION TO
in 1986 were defining moments in nanotechnology. The
SMALL, COMPLEX SYSTEMS
atomic force microscope has allowed engineers and sciSuccessfully managing the issues surrounding emerentists to view atoms. This ability to “see” has led to
gence, system complexity, and the top-down vs. bottomvarious investigations and the ability to manipulate
up design philosophy is a key factor in determining the
individual atoms.
viability of microelectronic- and nanotechnology-based
The issue of scale and the possibility of manipuproducts. Systems engineering principles provide the
lating the structure of materials on an atomic basis
JOHNS HOPKINS APL TECHNICAL DIGEST, VOLUME 31, NUMBER 1 (© 2012)
SYSTEMS ENGINEERING AT THE NANOSCALE
While nanotechnology applications and funding are increasing, there is growing concern
about the health risks associated
with nanoparticles and nanomaterials. These concerns spring
from lack of knowledge about
certain factors that are necessary
for predicting human health risks.
Such factors include the types of
exposure and particle entrance
into the body, movement of particles from the entry site (translocation), and interaction of the
material with the body’s biological systems. Once exposed, the
health risks are related to the
level and time of exposure, the
material’s toxicity, persistence of
the material in the body, and the
body’s susceptibility to the biologFigure 3. Size scales and development regimes for small, complex systems. Listed on the
ical effects. Experimental studies
right are examples of well-known objects in each of the size regimes.
in animals and with cell cultures
have shown that the toxicity of
ultrafine or nanoparticles is greater than the toxicity of
were first discussed by Richard Feynman in 1959 in
the same amount (mass) of larger particles of the same
his famous lecture, “There’s Plenty of Room at the
chemical composition.38
Bottom.”36 The “bottom” is now labeled nanotechInhalation is the most common route for exposing the
nology, a phrase coined by K. E. Drexler,37 who was
body to airborne particles. The deposition of nanoparattempting to describe advanced capabilities based on
ticles in the respiratory tract is determined primarily by
molecular assemblers. The word “nanotechnology” is
the particles’ size and shape (aerodynamics) rather than
now used to describe or label a diverse array of entiby their composition. Nanoparticles, being so small, are
ties and activities, all involving some aspect at the
not readily exhaled like their larger counterparts; thus
nanoscale. Clearly these materials, with dimensions
they can build up at faster rates in the respiratory tract
of less than 100 nm, encompass a variety of entities
and lungs. More research is needed on the effects of
including integrated circuit components, nanocrystals,
nanoparticle inhalation on health.
and CNTs. Figure 3 illustrates various size scales and
Ingestion is another way nanoparticles can enter the
gives examples of well-known objects in each of the
body.
Unless special precautions are taken, the accidensize regimes.
tal transfer of materials from hand to mouth is common
in handling of most substances. Similarly, ingestion
could occur by swallowing mucous that contains parNANOMATERIALS AND HEALTH AND
ticles inhaled through the respiratory tract. The effects
ENVIRONMENTAL SAFETY
of ingestion of nanoparticles are unknown.
Nanotechnology has become ubiquitous in our sociRecent reports indicate that nanoparticles can penety. Areas of application are diverse, from medicine to
etrate the skin. They penetrate by a standard diffusion
electronics. In electronics, nanoparticles have been
process and tend to collect in the epidermal and dermal
incorporated into adhesives and coatings as well as
layers. Potential harmful effects of these nanoparticle
interconnecting materials. Nanotubes and nanowires
accumulations in the body’s outer covering are again
are used as sensors, are incorporated in improved elecunknown. However, studies of cells have shown that
trical and thermal conductors, and are starting to make
CNTs can enter cells and cause release of cytokines,
appearances as active devices for space applications.
which cause inflammation, produce oxidative stress,
More than 50,000 publications on nanotechnology
and decrease culture viability—thus indicating potenideas came out in 2008; 13 nations produced more than
tial occupational hazards. One study (based on animal
1,000 publications each, and an additional 32 nations
models) estimated that a 20-day exposure to single-wall
had nanotechnology publication numbers ranging from
CNTs at the Occupational Safety and Health Adminis100 to 1,000.
tration (OSHA) permissible exposure limit posed a high
JOHNS HOPKINS APL TECHNICAL DIGEST, VOLUME 31, NUMBER 1 (© 2012)
55­­­­
J. L. SAMPLE AND H. K. CHARLES JR.
risk of development of lung lesions. Given the potential risks, workers should take every precaution to avoid
inhalation, ingestion, and contact of skin with nanotubes and particles.
FUTURE
Many issues must be explored before nanosystems can
be realized and integrated into society. As the potential
for large-scale integration is considered, for example, the
following issues will be relevant:
• System design tools: new tools may be required
• Material suppliers and their consistency: standardization of nanomaterials may be needed
• Reliability: smaller scaling may lead to higher failure rates
• Architecture: redundancy may counter effects of
smaller scaling
• Circuit manufacturing technology
• Circuit architectures
• Toxicity
• Public fear/marketing
• Cost
• Profit margin
• Unforeseen risks
Organizations exist to address most of these issues,
from organizations devoted to raising awareness of
the benefits, dangers, and possibilities for responsible
use of advanced nanotechnology39 to organizations
tracking nanotechnology-based consumer products,
their toxicity, and their geographical manufacture.40
Nanoelectronic architectures have prompted extensive
research, as self-assembling components may lead to
cheaper manufacture but higher defect densities. Such
self-assembling components could be incorporated
into the designs by using architectural redundancy or
software algorithms (as discussed in the conference
proceedings at http://www.nanoarch.org). All these factors may enable or inhibit the integration of nanosystems into mainstream application, regardless of their
inherent promise.
REFERENCES AND NOTES
1International
Council of Systems Engineering (INCOSE), A Consensus of the INCOSE Fellows, http://www.incose.org/practice/
fellowsconsensus.aspx (2 Oct 2006).
2Maier, M. W., and Rechtin, E., The Art of Systems Architecting, 2nd
Ed., CRC Press, London (2000).
3Abbott, R., “Putting Complex Systems to Work,” Complexity 13(2),
30–49 (2007).
4Brown, E. N., White, S. R., and Sottos, N. R., “Fatigue Crack Propagation in Microcapsule-Toughened Epoxy,” J. Mater. Sci. 41(19),
6266–6273 (2006).
56
5Huergo,
J., and Buckley, M., “Johns Hopkins Applied Physics Laboratory Names Inventions of the Year: Nanoporous Nucleic Acid
Sensor,” APL Press Release, http://www.jhuapl.edu/newscenter/
pressreleases/2007/070417.asp (17 Apr 2007).
6Sain, M., and Oksman, K. (eds.), “Introduction to Cellulose Nanocomposites,” Chap. 1, ACS Symposium Series 938: Cellulose Nanocomposites: Processing, Characterization, and Properties, American Chemical Society, Washington, DC, pp. 2–8 (2006).
7Holland, J. H., Adaptation in Natural and Artificial Systems: An Introductory Analysis with Applications to Biology, Control, and Artificial
Intelligence, MIT Press, Cambridge, MA (1992).
8Poincaré, J. H., “Sur le Probléme des Trios Corps et les Equations de la
Dynamique,” Acta Math. 13(1), 1–270 (1890).
9Lorenz, E. N., “Deterministic Nonperiodic Flow,” J. Atmos. Sci. 29(2),
130–141 (1963).
10Kalsin, A. M., Fialkowski, M., Paszewski, M., Smoukov, S. K., Bishop,
K. J. M., and Grzybowski, B. A., “Electrostatic Self-Assembly of
Binary Nanoparticle Crystals with a Diamond-Like Lattice,” Science
312(5772), 420–424 (2006).
11Chang, K., “Tiny Is Beautiful: Translating ‘Nano’ Into Practical,”
NY Times, 22 Feb 2005.
12Slocik, J. M., Zabinski, J. S. Jr., Phillips, D. M., and Naik, R. R., “Colorimetric Response of Peptide-Functionalized Gold Nanoparticles to
Metal Ions,” Small 4(5), 548–551 (2008).
13Haick, H., “Chemical Sensors Based on Molecularly Modified Metallic Nanoparticles,” J. Phys. D: Appl. Phys. 40(23), 7173–7186 (2007).
14Papadakis, S. J., Miragliotta, J. A., Gu, Z., and Gracias, D. H., “Scanning Surface-Enhanced Raman Spectroscopy of Silver Nanowires,”
in Plasmonics: Metallic Nanostructures and Their Optical Properties III,
M. I. Stockman (ed.), Proc. of SPIE, Vol. 5927, SPIE, Bellingham,
WA, pp. 337–344 (2005).
15Sample, J. L., Papadakis, S. J., Fitch, M. J., and Miragliotta, J. A.,
“Microfabricated Substrates for Spectroscopy and Separation,” in
Imaging, Manipulation, and Analysis of Biomolecules and Cells: Fundamentals and Applications III, D. V. Nicolau, J. Enderlein, R. C. Leif, D.
L. Farkas, and R. Raghavachari (eds.), Proc. of SPIE, Vol. 5699, SPIE,
Bellingham, WA, pp. 531–538 (2005).
16Shin, J.-S., and Pierce, N. A., “A Synthetic DNA Walker for Molecular Transport,” J. Am. Chem. Soc. 126(35), 10834–10835 (2004).
17Srinivasan, R., Baird, L., and Deacon, R., “Metal Nanotubes and Their
Applications in Micro Power Sources,” ECS Trans. 16(26), 73 (2009).
18Kustandi, T. S., Samper, V. D., Yi, D. K., Ng, W. S., Neuzil, P., and
Sun, W., “Self-Assembled Nanoparticles Based Fabrication of Gecko
Foot-Hair-Inspired Polymer Nanofibers,” Adv. Function. Mat. 17(13),
2211–2218 (2007).
19Mulreany, D. G., Chae, J. J., Guo, Q., Espinoza, F. A., Strehin, I., et al.,
“Collagen Vitrigels with Chondroitin-Sulfate Adhesive for Repair of
Full-Thickness Corneal/Scleral Injury,” in Proc. 27th Army Science
Conf., Orlando, FL, paper KP-08 (2010).
20Roco, M. C., “Nanoscale Science and Engineering: Unifying and
Transforming Tools,” AIChE J. 50(5), 890–897 (2004).
21de Micheli, G., Leblebici, Y., Gijs, M., and Vörös, J. (eds.), Nanosystems
Design and Technology, Springer, Berlin (2009).
22Flood, A. H., Stoddart, J. F., Steuerman, D. W., and Heath, J. R.,
“Whence Molecular Electronics?” Science 306(5704), 2055–2056
(2004).
23Avouris, P., Chen, Z., and Perebeinos, V., “Carbon-Based Electronics,”
Nat. Nanotechnol. 2(10), 605–615 (2007).
24Geim, A. K., and Novoselov, K. S., “The Rise of Graphene,” Nat. Mat.
6(3), 183–191 (2007).
25Love, J. C., Estroff, L. A., Kriebel, J. K., Nuzzo, R. G., and Whitesides,
G. M., “Self-Assembled Monolayers of Thiolates on Metals as a Form
of Nanotechnology,” Chem. Rev. 105(4), 1103–1170 (2005).
26Cho, J. H., and Gracias, D. H., “Self-Assembly of Lithographically
Patterned Nanoparticles,” Nanoletters 9(12), 4049–4052 (2009).
27Yan, H., Park, S. H., Finkelstein, G., Reif, J. H., and LaBean, T. H.,
“DNA-Templated Self-Assembly of Protein Arrays and Highly Conductive Nanowires,” Science 301(5641), 1882–1884 (2003).
28Breidenich, J., Patrone, J., Kelly, L., Benkoski, J., Le, H., and Sample,
J., “Chemiluminescent Solid Lipid Nanoparticles (SLN) and Interactions with Intact Skin,” in Biosensing II, M. Razeghi and H. Mohseni
(eds.), Proc. of SPIE, Vol. 7397, SPIE, Bellingham, WA, pp. 73970L-1–
73970L-10 (2009).
JOHNS HOPKINS APL TECHNICAL DIGEST, VOLUME 31, NUMBER 1 (© 2012)
SYSTEMS ENGINEERING AT THE NANOSCALE
29Kilby,
J. S., “Invention of the Integrated Circuit,” IEEE Trans. Electron. Devices 23(7), 648–654 (1976).
30Jack St. Clair Kilby (1923–2005), an engineer and inventor with
Texas Instruments, who received the Nobel Prize in Physics in 2000.
31Berlin, L., The Man Behind the Microchip: Robert Noyce and the Invention of Silicon Valley, Oxford University Press, New York (2005).
32Robert Norton Noyce (1927–1990) was a cofounder of Fairchild Semiconductor in 1957 and Intel in 1968 and is credited by many as the
inventor (along with Kilby) of the integrated circuit.
33Iijima, S., “Helical Microtubules of Graphite Carbon,” Nature
354(6348), 56–58 (1991).
34There is still some controversy over who invented (grew) the first
nanotube. While widely attributed to Iijima, some still feel that Radushkevich working in Russia in the early 1950s was the true inventor.
The invention of the single-wall CNT, however, is well known, and
credit for its invention is jointly shared by Iijima and Ichibashi from
Japan and an IBM California team led by Bethune.
35Binnig,
G., Quate, C. F., and Gerber, C., “Atomic Force Microscope,”
Phys. Rev. Lett. 56(9), 930–933 (1986).
36Feynman, R. P., “There’s Plenty of Room at the Bottom,” Eng. Sci. 23,
22–36 (1960).
37Drexler, K. E., Nanosystems: Molecular Machinery, Manufacturing, and
Computation, John Wiley & Sons, New York (1992).
38Oberdörster, G., Oberdörster, E., Oberdörster, J., “Nanotechnology:
An Emergency Discipline Evolving from Studies of Ultrafine Particles,” Environ. Health Persp. 113(7), 823–835 (2005).
39Hart Research Associates, Nanotechnology, Synthetic Biology, & Public
Opinion: A Report of Findings Based on a National Survey Among
Adults, Hart Research Associates, Washington, DC, http://www.
nanotechproject.org/process/assets/files/8286/nano_synbio.pdf (2009).
40Since its establishment in 2005, the Project on Emerging Nanotechnologies has generated an ongoing inventory of nanotechnologybased consumer products currently on the market (http://www.
nanotechproject.org/inventories/consumer/).
The Authors
Jennifer L. Sample supervises a section working on materials and nanostructures for primarily aerospace applications, including coatings, power
management, self-healing materials, bionanomaterials, soft materials, and
stimulus-responsive materials. Dr. Sample also is an experienced principal
investigator, project manager, and physical chemist, studying and applying
nanomaterials to homeland defense and space exploration applications,
specifically engineered multifunctional materials, polymer nanocomposJennifer L.
Harry K.
ites, refractory nanomaterials, and nanoscale bioconjugation and tagging.
Sample
Charles Jr.
She has experience in sensor systems and materials-based thermal management. Harry K. Charles Jr. has an extensive background in the development and packaging of miniaturized electronic, electro-optic, and electromechanical devices, assemblies, and systems
for use in a wide variety of stringent environments, including space, underwater, avionic, and biomedical environments.
His experience includes the design, modeling, and analysis of semiconductor and precision material structures, including
transistors, integrated circuits, optoelectronic devices, MEMS, and novel sensors. An authority on electronic packaging,
Dr. Charles is recognized internationally for his work in interconnection, wirebond testing, thin- and thick-film circuitry,
multichip modules, and ultrathin and flexible circuitry. He is a Principal Staff Engineer in the Research and Exploratory
Development Department. For further information on the work reported here, contact Jennifer Sample. Her e-mail
address is jennifer.sample@jhuapl.edu.
The Johns Hopkins APL Technical Digest can be accessed electronically at www.jhuapl.edu/techdigest.
JOHNS HOPKINS APL TECHNICAL DIGEST, VOLUME 31, NUMBER 1 (© 2012)
57­­­­